Systems for real-time contamination, environmental, or physical monitoring of a photomask

ABSTRACT

Systems for real-time contamination, environmental, or physical monitoring of a photomask. The system includes an electronics package physically mounted to the photomask and a processing device in communication with the electronics package. The electronics package includes a sensor configured to monitor the attribute and generate sensor data. The processing device is configured to analyze the sensor data communicated from the electronics package to the processing device.

BACKGROUND

The invention relates generally to integrated circuit fabrication and,in particular, to systems for use in real-time monitoring of anattribute of a photomask.

Semiconductor manufacturers fabricate integrated circuits usingphotolithographic processes that rely upon a series of differentphotomasks to define different structural features characteristic of thecircuit. The pattern engrained on each photomask is designed to conformto dimensional rules that ensure that the patterns transfer properly andthat the integrated circuit functions properly. Once the layout iscreated as a pattern on the photomask, the photolithographic processutilizes an exposure tool to project the mask pattern onto a photoresistlayer carried on the semiconductor wafer.

Among other process variables, a satisfactory product yield iscontingent upon having essentially defectless masks and reticles.Photomask deployment may result in relatively high mean time to detect(MTTD) for the appearance of new mask-related defects or the occurrenceof mask degeneration. Poor handling of a photomask may dislodgeotherwise innocuous particulates and cause relocation to positions onthe photomask that ultimately cause defects in the wafers fabricatedusing the photomask. In any event, degradation of the photomask fromcontamination, as well as an abnormal environmental factor or eventsoccurring during handling, may cause yield loss in the integratedcircuits fabricated using the photomask.

As an important step associated with the photolithography process, waferfabricators periodically inspect every photomask after a fixed number ofwafer passes to determine the condition of the photomask. Unfortunately,high-resolution mask inspection tools, such as CCD imaging systems, aretypically only found in mask fabrication shops. Because of the absenceof a high-resolution mask inspection tool, wafer fabricators may haveonly a limited ability to monitor the photomask condition. In any event,conventional approaches for photomask inspection do not providereal-time monitoring of contamination on the photomask, the environmentof the photomask, or a physical attribute of the photomask.

Accordingly, there is a need for improved systems to acquire and analyzea real-time contamination, environmental, or physical attribute of aphotomask.

BRIEF SUMMARY

In an embodiment of the invention, a system for monitoring an attributeof a photomask includes an electronics package physically mounted to thephotomask and a processing device in communication with the electronicspackage. The electronics package includes a sensor configured to monitorthe attribute and generate sensor data. The processing device isconfigured to analyze the sensor data communicated from the electronicspackage to the processing device.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate various embodiments of theinvention and, together with a general description of the inventiongiven above and the detailed description of the embodiments given below,serve to explain the embodiments of the invention.

FIG. 1 is a side view of a photomask assembly including a pellicle, aphotomask, and a sensor.

FIG. 2 is a diagrammatic view of a system including the photomaskassembly of FIG. 1 in accordance with an embodiment of the invention.

FIG. 3 is a block diagram of an exemplary hardware and softwareenvironment for a processing device suitable for interfacing with thephotomask assembly in FIGS. 1 and 2.

FIG. 4 is a diagrammatic view of a system including the photomaskassembly of FIG. 1 in accordance with an alternative embodiment of theinvention.

DETAILED DESCRIPTION

Embodiments of the invention relate to systems for monitoring aphotomask with a sensor that is physically coupled with the photomask.The sensor is operative to monitor one or more attributes of thephotomask or events that occur related to the photomask of the assembly.In particular, the sensor is configured to monitor or detect eventsrelated to the photomask in real-time as the photomask is used during amanufacturing process to manufacture an integrated circuit chip or whilethe photomask is in storage. The sensor can communicate over a wiredconnection, or wirelessly, with a control system of a lithography tool,a control system of a reticle storage unit, or a lithography computercontrol system. The control system analyzes the sensor data and, ifappropriate, reacts to information contained within the sensor data. Thereaction may be to take an action related to quality control. Thecontrol system may also analyze the sensor data for the existence ofhistorical trends.

With reference to FIG. 1, a photomask assembly 10 is configured to becoupled with an optical aligner, such as a stepping projection aligneror stepper, and used in conjunction with a lithography tool 60 (FIG. 2)in a chip manufacturing line to generate a pattern in a photoresistlayer applied to a wafer. To transfer the pattern to the photoresistlayer, the photomask assembly 10 is suspended above the wafer and a fluxof ultra-violet light, X-rays, or other type of electromagneticradiation is directed from the lithography exposure system through thephotomask assembly 10 and toward the wafer.

The photomask assembly 10 includes a photomask 12 and a pellicle 14. Thephotomask 12 includes a substantially flat substrate or plate 18 of amaterial like quartz or glass and a layer 20 of a material, such aschromium or chromium oxynitride, applied on one side. The layer 20 isetched, stopping on the plate 18, to impart a pattern of opaque andnon-opaque regions on the plate 18. The opaque regions and non-opaqueregions of layer 20 correspond to a pattern representing features in anintegrated circuit design.

An image of the opaque and non-opaque regions in the metal layer 20 isprojected onto a layer of photoresist carried on the semiconductor waferby directing the electromagnetic radiation through the photomask 12 andtoward the wafer. The photomask 12 includes an active area in the formof a mask field 15 containing the opaque and non-opaque regions that areimaged onto the photoresist layer of the wafer. The photomask 12 mayincorporate a pattern large enough to pattern an entire wafer with eachexposure or, alternatively, may function as a reticle containing apattern for one or more die but not large enough to transfer awafer-sized pattern in a single exposure.

Non-opaque regions transmit electromagnetic radiation of the wavelengthused by the exposure system using the photomask 12 through the plate 18un-attenuated. Opaque regions attenuate or completely block theelectromagnetic radiation to a degree. The electromagnetic radiationexposes the photoresist with an image of the pattern of opaque andnon-opaque regions. Alternatively, the photomask 12 may include regionsof modulated thickness that effectively define the opaque and non-opaqueregions that are imaged with phase shifting onto the photoresist layer.

The pellicle 14 is constructed of a pellicle frame 22 and a thintransparent film or membrane 24 secured peripherally to the frame 22.The photomask 12 further includes a non-active area in the form of anannular border 17 that is spatially located between the frame 22 of thepellicle 14 and the mask field 15. The annular border 17 is not imagedonto the photoresist layer on the wafer. The frame 22 is physicallyaffixed or attached to the photomask 12 such that one surface of thetransparent membrane 24 is held at a fixed distance from the confrontingsurface of the photomask 12. The frame 22, which is typically acontinuous and unbroken ring, may be adhesively bonded to the peripheryof the photomask 12 to affix the pellicle 14 to the photomask 12. Theframe 22 may be a single-thickness wall composed of a hard plastic or,alternatively, a metal such as aluminum or an aluminum alloy. Thetransparent membrane 24 may be composed of an organic material, such asnitrocellulose or cellulose acetate, and may be fluoropolymer coated.

The pellicle 14 operates to isolate a self-contained, controlledenvironment consisting of an enclosed space 25 bordered or boundedspatially by the frame 22, the transparent membrane 24, and photomask12. The attribute that is controlled within the controlled environmentof the enclosed space 25 may comprise one or more of temperature,humidity, chemical composition of the atmosphere, air pressure,particulate count, or combinations of these attributes. The pellicle 14primarily functions to shield the photomask 12 against contaminationoriginating from the cleanroom environment. The image of any foreignmatter or contamination collected on the transparent membrane 24 is notreproduced in the photosensitive resist layer residing on the waferbecause the separation between the transparent membrane 24 and photomask12 places any collected contamination at a location that, duringexposure, is projected in an out of focus condition in the plane of thewafer.

In an alternative embodiment of the invention, the pellicle 14 may beomitted from the photomask 12. Certain types of photomasks 12 may notrequire the protection afforded by a pellicle 14, such as photomasks 12that are used in conjunction with X-rays originating from thelithography exposure system.

With reference to FIGS. 1 and 2, the photomask assembly 10 furtherincludes an electronics package 28 with a sensor 30, a processor 32, abus 34 connecting the processor 32 to the sensor 30, a memory 36, and abus 38 connecting the processor 32 to the memory 36. The electronicspackage 28 further includes an analog I/O circuit 40 and a digital I/Ocircuit 42 that are both connected to processor 32 by a bus 44. Theelectronics package 28 further includes a transceiver 46 that isconnected by a bus 48 to the analog I/O circuit 40 and digital I/Ocircuit 42 and, thereby, by bus 44 with the processor 32. The processor32 includes any circuitry required to operate the sensor 30 oradditional circuitry may be included in the electronics package 28 butexternal to the processor 32. A portion of the circuitry may also becarried on board the sensor 30.

Transceiver 46 has an antenna 50 used by the electronics package 28 totransmit sensor readings to a processing device 100 (FIG. 3) of thelithography tool 60, a reticle storage unit 62, or a lithographycomputer control system 64. The lithography computer control system 64may be a central server that supervises multiple lithography tools. Thetransceiver 46 may also rely on the antenna 50 to receive programming orcontrol signals, such as power on, power off, schedule sensor operationsuch as a frequency for sampling the attribute, setup information suchas how the date is collected or stored, communicate sensor data, andpoll, relating to modes of operation for the electronics package 28communicated from the lithography tool 60, reticle storage unit 62, orcontrol system 64. In an embodiment, the electronics package 28 may beinformed of the specific platform in which it is disposed, either thelithography tool 60 or the reticle storage unit 62, and the operatingparameters of the platform may be adjusted. For example, when inproduction and inside the temperature and humidity controlledenvironment of the lithography tool 60, the electronics package 28 maybe optionally powered of as attributes like temperature and humidity arenot of interest.

In certain alternative embodiments, the transceiver 46 can be replacedwith a different type of transmitter that lacks signal-receivingcapabilities but, instead, is limited to sending signals. The sensorreadings, as well as any programming or control signals, may betransmitted and received by the transceiver 46 according to any suitableencoding and modulating scheme. In one embodiment, the antenna 50 maycomprise the frame 22 of the pellicle 14, which is an existing physicalstructure of the photomask assembly 10, so that an additional discreteantenna structure is not required. The connection between the pellicleframe 22 and the analog I/O circuit 40 and digital I/O circuit 42 areestablished in a manner understood by a person having ordinary skill inthe art. In an alternative embodiment, the transceiver 46 may be omittedin its entirety, and replaced by a wired connection with the lithographytool 60, reticle storage unit 62, or control system 64. For example, awired connection 66 may be established between a staged position 68inside the lithography tool 60 and the analog I/O circuit 40 of theelectronics package 28.

The electronics package 28 is powered by a power source 52, which may bea rechargeable and/or replaceable battery. In other embodiments, thepower source 52 may be solar cell that is stationed in the electronicspackage 28 and positioned relative to the pellicle 14 at a location thatis illuminated by the electromagnetic energy directed through thephotomask 12. Such power sources 52 have conventional constructionsunderstood by a person having ordinary skill in the art.

The electronics package 28 and, therefore, the sensor 30 are physicallycoupled with the photomask 12, the pellicle 14, or both by, for example,one or more adhesive bonds. In the representative embodiment, theelectronics package 28 is directly physically attached to the photomask12 at a location inside the perimeter established by the frame 22 of thepellicle 14 and within the enclosed space 25. However, the electronicspackage 28 is located in the annular border 17 of the photomask 12 suchthat the electronics package 28 does not occlude the transmission ofelectromagnetic energy through the mask field 15 of the photomask 12. Inother words, the electronics package 28 has a footprint on the photomask12 that is confined within the annular border 17. In an alternativeembodiment, the electronics package 28 may have a direct, physicallycoupling with the frame 22 of the pellicle 14, instead of the photomask12, such that the frame 22 is an intervening structure that facilitatesan indirect, physical coupling between the electronics package 28 andthe photomask 12.

The sensor 30 may have a construction, as understood by a person havingordinary skill in the art, imparting the capability of detecting one ormore contamination, environmental, or physical events or attributesrelated to the photomask 12 in real-time as the photomask 12 is usedduring a manufacturing process to manufacture an integrated circuitchip. The real-time monitored attributes or events monitored by sensor30 may include, but are not limited to, the presence of chemicalcontamination in the atmosphere inside the enclosed space 25, thetemperature of the atmosphere inside the enclosed space 25, atemperature of the photomask 12, a humidity inside the enclosed space25, accelerations, shocks, or vibrations experienced by the photomask 12during handling and storage, an optical flux through the photomask 12,electrostatic discharge (ESD) events or environment such as ambientelectrical fields experienced by the photomask 12, the presence offoreign material or particulates inside the enclosed space 25, and airpressure inside the enclosed space 25.

If the pellicle 14 is omitted from the construction, then monitoredattribute is not necessarily tied to the enclosed space 25 as theenvironment is not closed. In this instance, the sensor 30 may sense thepresence of chemical contamination in the ambient environment near thephotomask 12, a temperature of the ambient environment near thephotomask 12, a temperature of the photomask 12, a humidity of theambient environment near the photomask 12, accelerations, shocks, orvibrations experienced by the photomask 12 during handling or storage,an optical flux through the photomask 12, electrostatic discharge (ESD)events or environment such as electrical fields experienced by thephotomask 12, the presence of foreign material or particulates in thevicinity of the photomask 12, and the air pressure of the ambientenvironment near the photomask 12.

In one embodiment, the sensor 30 may be a chemical transducer configuredto sense the presence of elemental gases like oxygen, hydrogen, orchlorine, ammonia, water, hydrogen fluoride, hydrogen chloride, nitrogenoxides, silanes, alcohols, ketones, esters, amines, solvents,chlorinated solvents, or fluoridated solvents. In addition to presence,the sensor 30 may be capable of monitoring the concentration of one ormore chemical contaminants sensed in the ambient environment. In anotherembodiment, the sensor 30 may be a thermistor or thermocouple capable ofoutputting a signal from which temperature readings can be deduced andtemperature changes can be detected. For example, the detectedtemperature changes may be used for temperature control of theenvironment of the photomask 12. In yet other embodiments, the sensor 30may comprise an accelerometer configured for measuring accelerations,shocks, or vibrations of the photomask 12 imparted during handling orstorage, a humidity transducer configured for monitoring relativehumidity, or a pressure transducer for sensing the pressure level of thegases in the surrounding atmosphere. In yet another embodiment, thesensor 30 may comprise a photoelectric type particulate sensor or anionization type particulate sensor that is configured to monitor for thepresence of particulates or other foreign matter.

The sensor 30 generates sensor data representing the measured attribute.The electronics package 28 may continuously transfer the sensor data inreal time to the lithography tool 60, reticle storage unit 62, orcontrol system 64. Alternatively, the electronics package 28 maytransfer sensor data intermittently or periodically to the lithographytool 60, reticle storage unit 62, or control system 64. Alternatively,the electronics package 28 may transfer stored sensor data to thelithography tool 60, reticle storage unit 62, or control system 64 onlywhen polled by one of these external sources.

In yet another alternative embodiment, the electronics package 28 maystore the sensor data and transfer the stored data intermittently orperiodically to the lithography tool 60, reticle storage unit 62, orcontrol system 64. For example, the electronics package 28 may storesensor data over time that, when communicated by the electronics package28 to the lithography tool 60, reticle storage unit 62, or controlsystem 64, is used in diagnosing a source of contaminants or other typesof analysis. Typically, the data storage in the memory 36 of theelectronics package 28 is short term in comparison with long term datastorage at the lithography tool 60, reticle storage unit 62, or controlsystem 64.

The electronics package 28 may also be configured to communicate anidentification (ID) code to the lithography tool 60, reticle storageunit 62, or control system 64 in response to a poll signal or otherquery from one of these external sources. With the assistance of the IDcode, the electronics package 28 may have the ability to communicatedata from multiple sensors either in a coded data stream or on severalfrequencies at the same time. The ID code may be broadcast and used toidentify the photomask 10 for retrieval from the reticle storage unit62. The sensor readings, as well as any control signals and any ID code,may be stored in the memory 36 on board the electronics package 28,which facilitates intermittent communication of the sensor readings.

The lithography tool 60 includes the optical aligner and a source of theflux of ultra-violet light, X-rays, or other type of electromagneticradiation that is directed from an exposure system of the lithographytool 60 through the photomask assembly 10 and toward the photoresist onthe wafer. The lithography tool 60 may locally store a small number ofphotomask assemblies each similar or identical to photomask assembly 10.Of this small number of photomask assemblies, one is typically installedin a manufacturing position and the rest are waiting to be installed aspart of a manufacturing sequence. The reticle storage unit 62 is anautomated storage cabinet that includes a trackable set of locationsused to store multiple photomask assemblies each similar or identical tophotomask assembly 10. The reticle storage unit 62 is intended forrelatively long term physical storage of the photomask assembly 10.

The control system 64 may function as an administrator for thelithography tool 60 and reticle storage unit 62, as well as otherlithography tools and reticle storage units (not shown). The controlsystem 64 may communicate a process recipe to the lithography tool 60,receive data from a metrology tool used to adjust a process recipe,store processing information about a lot of wafers sent to thelithography tool 60, etc.

The lithography tool 60 has a transceiver 70 equipped with an antenna 72that is used to communicate with the transceiver 46 of the electronicspackage 28 via antenna 50. Similarly, the reticle storage unit 62 has atransceiver 74 equipped with an antenna 76 that is used to communicatewith the transceiver 46 of the electronics package 28 via antenna 50.The control system 64, which may be also has a transceiver 78 equippedwith an antenna 80 that is used to communicate with the transceiver 46of the electronics package 28 via antenna 50.

At any instant in time, the electronics package 28 may bi-directionallyor uni-directionally communicate with either the lithography tool 60,the reticle storage unit 62, or the control system 64. However, undercertain circumstances, the electronics package 28 may concurrently orintermittently talk with two or all of these partners. In addition toreceiving a continuous or intermittent stream of sensor readings fromthe electronics package 28, the lithography tool 60, reticle storageunit 62, or control system 64 may communicate programming or controlsignals, such as power on, power off, schedule sensor operation,communicate sensor data, and poll to prompt the transfer of sensor data,as commands to the electronics package 28. As an example, control may beexercised over the operation of the electronics package 28 by power onand power off commands to limit confusion in an environment thatfeatures multiple photomasks 10 each with a distinct electronics package28. As another example, the electronics package 28 may be powered ofduring periods over which the attribute does not require monitoring.

The electronics package 28 may be used as a smart device by supplyingthe processor 32 with programming to take certain action in response tothe sensor data or to pre-analyze the sensor data in some way. Forexample, the electronics package 28 may be programmed to only transmitsensor data using transceiver 46 if the monitored attribute is outsideof a certain range or is present at certain times as an out-of-toleranceevent. Control may be exercised, as examples, to set different presettemperature or contamination limits depending on the environment (i.e.,installation in the lithography tool 60 or storage in the reticlestorage unit 62) of the photomask 10. As a specific example, theelectronics package 28 may be programmed to trigger the transfer oftemperature data acquired with sensor 30 to the lithography tool 60,reticle storage unit 62, or control system 64 only if the measuredtemperature of the photomask 10 exceeds 80° C. or, alternatively, thetemperature of the ambient environment of the photomask 10 exceeds 80°C.

In an alternative embodiment, the transceiver 46 may be omitted in itsentirety, and replaced by a wired connection 66 with, for example, thelithography tool 60. For example, the wired connection 66 may beestablished between a staged position 68 of the lithography tool 60 andthe analog I/O circuit 40. At the staged position 68, temporary closedelectrical connections are established between an interface at thestaged position and the analog I/O circuit 40 and/or the digital I/Ocircuit 42. The staged position 68 may be a manufacturing location inthe lithography tool 60 or another location at which the photomaskassembly 10 is temporarily stored while awaiting transfer to themanufacturing location.

With reference to FIG. 3, the lithography tool 60, reticle storage unit62, and control system 64 each include a processing device 100 used toreceive and analyze the sensor data communicated from the electronicpackage 28 carried by the photomask 10. In the following description,this equivalence is assumed in the description of the processing device100, which is described below in the context of the lithography tool 60but is understood to apply equally to the reticle storage unit 62, andcontrol system 64.

Processing device 100 has the representative form of a computer thattypically includes at least one processor 102 and a memory 104 coupledwith the processor 102. The processor 102 is operatively coupled withthe transceiver 70 that receives signals sent from the electronicpackage 28 at the photomask 10. Processor 102 may represent one or morediscrete processors (e.g. microprocessors) and memory 104 may representthe random access memory (RAM) devices comprising the main storage ofprocessing device 100, as well as any supplemental levels of memory,e.g., cache memories, non-volatile or backup memories (e.g. programmableor flash memories), read-only memories, etc. In addition, memory 104 maybe considered to include memory storage physically located elsewhere inprocessing device 100, e.g., any cache memory in a processor 102, aswell as any storage capacity used as a virtual memory, e.g., as storedon a mass storage device 106. The mass storage device 106 may contain acache or other data storage, which may include one or more databases108, used to store sensor data acquired by the sensor 30 andcommunicated to the processing device 100 from the electronics package28 (FIG. 2).

Processing device 100 also typically receives a number of inputs andoutputs for communicating information externally. For interfacing with auser or operator, processing device 100 typically includes one or moreuser input devices 110 (e.g., a keyboard, a mouse, a trackball, ajoystick, a touchpad, a keypad, a stylus, and/or a microphone, amongothers). Processing device 100 may also include a display 112 (e.g., aCRT monitor, an LCD display panel, and/or a speaker, among others) orother output device, such as a printer 114. The interface to processingdevice 100 may also be through an external terminal connected directlyor remotely to processing device 100, or through another computercommunicating with processing device 100 via a network 116, modem, orother type of communications device. Processing device 100 communicatesover the network 116 through a network interface 120. As examples, thelithography tool 60 or the reticle storage unit 62 may communicate withthe control system 64 via network 116.

Processing device 100 operates under the control of an operating system118 and executes or otherwise relies upon various computer softwareapplications, components, programs, objects, modules, data structures,etc. In general, the routines executed to implement embodiments of theinvention, whether implemented as part of an operating system or aspecific application, component, program, object, module or sequence ofinstructions will be referred to herein as “computer program code”, orsimply “program code”. The computer program code typically comprises oneor more instructions that are resident at various times in variousmemory and storage devices in a computer, and that, when read andexecuted by one or more processors in a computer, causes that computerto perform the steps necessary to execute steps or elements embodyingthe various aspects of the invention.

Upon receipt of the sensor data, the processing device 100 of thelithography tool 60, reticle storage unit 62, or control system 64evaluates the sensor data using computer program code, stores the sensordata for future evaluation using computer program code, transfers thesensor data to another processing device for evaluation, or performssome combination of these activities. Use or inspection decisions may bekeyed off the sensor data as a validation tool for quality control ofthe photomask 10. For example, if an ESD event is detected by sensor 30while photomask 10 is loaded in a manufacturing position in thelithography tool 60 and communicated by the electronics package 28 (FIG.2) to the processing device 100, a decision may be made by theprocessing device 100 to halt processing, unload the photomask 10, andinspect it. As another example, if a temperature excursion of concern isdetected by sensor 30 while photomask 10 is stored in the reticlestorage unit 62 or during movement of photomask 10 between the reticlestorage unit 62 and the lithography tool 60, the occurrence may beflagged for the photomask 10 and a similar inspection decision tovalidate the mask integrity may be made.

In response to identifying these and other out-of-tolerance events forthe sensed attribute, the processing device 100 may be configured toperform one or more actions. As examples, the processing device 100 mayflag the photomask 10 for a quality control inspection, communicate tothe lithography tool 60 to stop production, store a flag that indicatesthat the photomask 10 needs an inspection, communicate to thelithography tool 60 to modify monitoring conditions, or perform somecombination of these actions. The sensor data communicated from theelectronics package 28 (FIG. 2) to the processing device 100 may also beaccumulated and used to track historical trends for the conditionsand/or events experienced by the photomask 10.

With renewed reference to FIG. 2 and in accordance with an alternativeembodiment, the electronics package 28 may include another sensor 54that is similar in function and construction to sensor 30. A bus 56connects the sensor 54 with the processor 32. In one embodiment, sensor54 may be configured to monitor a different attribute related to thephotomask 12 than sensor 30. Furthermore, sensor 54 may be integratedinto an additional electronics package (not shown) like electronicspackage 28 but separate from electronics package 28 and coupled with thephotomask 12. As may be appreciated, more than two sensors may beincorporated into the electronics package 28 and, in one embodiment,each of these sensors may be configured to sense different attributes ofthe photomask 12. Additional sensors, such as sensor 54, function toincrease the event and attribute monitoring capability of theelectronics package 28. Sensor 54 may communicate sensor data at adifferent frequency than the sensor 30 or may be instructed tocommunicate sensor data at a different time than sensor 30.

With reference to FIG. 4 in which like reference numerals refer to likefeatures in FIGS. 1 and 2 and in accordance with an alternativeembodiment of the invention, the electronics package 28 may alsocommunicate with a transceiver 86 associated with a mask holder 84. Themask holder 84 defines an enclosure that contains the photomask 10 fortemporary storage and transport. The transceiver 86 acts as anintermediary that relays sensor data from the electronics package 28 tothe lithography tool 60, reticle storage unit 62, or control system 64,as well as relaying signals from the lithography tool 60, reticlestorage unit 62, or control system 64 to the electronics package 28.

The transceiver 86 of the mask holder 84 also includes an antenna 88exterior of the physical enclosure for the photomask 10 defined by themask holder 84 and an antenna 90 within the physical enclosure for thephotomask 10 defined by the mask holder 84. The transceiver 86 relies onthe antenna 90 to receive signals from the transceiver 46 of theelectronics package 28, as well as forward any commands received fromthe lithography tool 60, reticle storage unit 62, or other controlsystem 64. The transceiver 86 uses the antenna 88 to send the signalsreceived from the electronics package 28 to the lithography tool 60,reticle storage unit 62, or other control system 64, as well as toreceive any commands originating from these sources.

It will be understood that when an element is described as being“attached”, “connected”, or “coupled” to another element, it can bedirectly connected or coupled to the other element or interveningelements may be present. In contrast, when an element is described asbeing “directly attached”, “directly connected”, or “directly coupled”to another element, there are no intervening elements present.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. Furthermore, to the extent that theterms “includes”, “having”, “has”, “with”, “composed of”, or variantsthereof are used in either the detailed description or the claims, suchterms are intended to be inclusive in a manner similar to the term“comprising.”

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present invention has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiment was chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. A system comprising: a photomask including a maskfield with a pattern of features configured to correspond to features ofan integrated circuit; a pellicle coupled with the photomask, thepellicle including a transparent membrane and a frame connecting thetransparent membrane with the photomask to define an enclosed spaceisolated from an ambient environment; an electronics package physicallymounted to the photomask and located inside the enclosed space, theelectronics package including a sensor configured to monitor anattribute and generate sensor data related to the attribute, a firsttransceiver, and a processor coupled with the sensor and coupled withthe transceiver; and a processing device in communication with theelectronics package, the processing device configured to analyze thesensor data communicated from the electronics package to the processingdevice, wherein the frame is coupled with the first transceiver so as tooperate as a first antenna for transmitting the sensor data from theelectronics package to the processing device.
 2. The system of claim 1wherein the processing device includes a second transceiver forbidirectional communication with the first transceiver of theelectronics package, and the processing device is further configured tocommunicate one or more control signals from the processing device tothe electronics package for use in controlling the operation of thesensor.
 3. The system of claim 1 wherein the electronics packageincludes a memory configured to store the sensor data, and theprocessing device is configured to communicate a control signal to theelectronics package to initiate a transfer of the sensor data from thememory to the processing device.
 4. The system of claim 1 wherein theattribute monitored with the sensor is chemical contamination,temperature, humidity, acceleration, shock, vibration, optical flux,electrostatic discharge events, particulates, or air pressure.
 5. Thesystem of claim 1 wherein the processing device is a component of acontrol system of a lithography tool, a control system of a reticlestorage unit, or a lithography computer control system.
 6. The system ofclaim 1 further comprising: a holder configured to store the photomask,the holder including a second transceiver configured to receive thesensor data from the electronics package, and the second transceiver ofthe holder further configured to communicate the sensor data to theprocessing device.
 7. The system of claim 1 wherein the processingdevice is further configured to store the sensor data for use in trendanalysis.
 8. The system of claim 1 wherein the processing device isfurther configured to identify an out-of-tolerance event from the sensordata and, in response to the out-of-tolerance event, perform one or moreof flagging the photomask for an quality control inspection,communicating to a lithography tool to stop production, storing a flagthat indicates that the photomask needs an inspection, or communicatingto the lithography tool to modify monitoring conditions.
 9. The systemof claim 1 wherein the processing device includes a second transceiverand a second antenna configured to communicate with the firsttransceiver and the first antenna of the electronics package.